USGS Puts Seismic Maps of San Francisco Bay Area Online

SAN FRANCISCO — The U.S. Geological Survey on Wednesday released new online maps of the San Francisco Bay area that show the region's geologic history and active earthquake faults.
The interactive digital maps are designed to help the public understand the risks of living in earthquake country and make preparations for potential disasters, USGS scientists said at the 100th Anniversary Earthquake Conference.

"By releasing these maps, we're trying to wake people up," said Russ Graymer, the USGS geologist who led the project. "Once they understand that there are dangerous faults throughout the Bay Area, they will take more seriously calls to prepare themselves."

One of the maps shows faults that where major earthquakes have erupted over the past 2 million years and where future temblors are expected. Visitors to the Web site can see where the historic quakes of 1868, 1906 and 1989 took place.

Another map shows the geologic materials and structures that make up the Bay Area, revealing the region's complex geologic history and showing which areas are most vulnerable to landslides or liquefaction.

"A geologic map is the alphabet through which stories of the earth can be told," said USGS Acting Director Patrick Leahy. "This is really ground zero of where the science begins."

The maps were released a day after San Francisco commemorated the 100th anniversary of the 1906 earthquake that killed thousands of people and set off fires that destroyed much of the city.